The present invention, in general, relates to filtering units and assemblies and, more particularly, relates to filter assemblies for use especially in connection with air conditioning or heating ducts.
As is well known in the art, many types of systems which utilize air purifying filters require that the filters employed be periodically removed and cleaned or replaced. Attempts have been made to design filter assemblies in a manner such that the filtering medium utilized can be removed without much difficulty. These attempts have failed in that the state-of-the-art filter assemblies still require complicated latch and locking mechanisms as well as tools to remove the filters or grills from the assemblies.
In addition, in many instances the filter assemblies are relatively bulky which is problematic in cases where an air conditioning return or a heating duct is located in a conspicuous place whose physical appearance or decor is important from the standpoint of aesthetics.
Also, in order to enable a filter grill assembly to be decorated to match its immediate surroundings, it is often desirable that the exterior or front of the grill extends more or less flush with the wall surrounding the duct. Such decoration may, for instance, be in the form of a trimming, molding or similar ornamental strip around the exterior marginal portions or sides of the assembly. Again, such type of ornaments are impossible to secure to the assembly exterior on account of either the bulkiness of the filter assembly or their exteriorly protruding latches or hinges which retain the filter or grill in position relative to the duct or air return.
Still further, prior art filter assemblies oftentimes require the use of unconventional or noncommercial filter media. Frequently, the filtering media have to meet special dimensional requirements or, in another instance, they may have to be compressible. Such special requirements as, for instance, size and shape or compressible or noncompressible filters form a major disadvantage encountered with prior art filtering systems.
One such conventional type of filter assembly is discussed in U.S. Pat. No. 3,250,063 to Andrews. This patent teaches a filter assembly which employs a pair of clip elements which engage around the front and back side of the filter. The filter has to be pushed into or pulled out of the clips. In addition, absent from the Andrews reference is an easily removable or replaceable filter or grill. Also, the Andrews patent is not aesthetically attractive or appealing to match the decor of a room or similar surrounding.
Another prior art filter assembly is taught in U.S. Pat. No. 2,981,367 to Sprouse. Sprouse utilizes two frames which are snapped into interengagement over a filter to retain the latter in the frames. Provided in Sprouse are latches or barbs utilized to maintain the filter in position, which results in compression of the filter. The disadvantage of this assembly is the necessity of having to remove the latches to free the filter. Also, the filter has to be compressible and, moreover, the Sprouse assembly is bulky and, thus, cosmetically unattractive.
In the patent to Burke, U.S. Pat. No. 3,243,942, a gas-filtering system is formed with a series of filters which extend in a zig-zag pattern within the filter frame. The filter employed in Burke is not easily removable.
From the above discussion of the prior art filter systems and assemblies, it will be apparent that it would be advantageous to provide a filter assembly which does not necessitate the use of exterior latch or lock mechanisms, which is desirable as regards its design and which employs conventional or commercially available filter elements.